No Evidence That Lupus Drugs Lead to Cancer, Says Study

MONDAY, Feb. 4 -- Drugs used to treat the autoimmune disease lupus do not significantly increase patients' risk of the blood cancer lymphoma, a new study says.

The findings should help reduce widely held fears about a link between lupus medication and lymphoma, said the researchers at McGill University in Montreal.

In people with systemic lupus erythematosus (SLE), the immune system attacks healthy tissue such as the skin, joints, kidneys and the brain. Medications to suppress the immune system are used to treat lupus, but previous research has suggested that this may put patients at increased risk for lymphoma.

Because of fears about developing cancer, some lupus patients are reluctant to take their medication, and others stop taking it.

This international study included 75 lupus patients who had lymphoma and nearly 5,000 cancer-free lupus patients. Researchers looked at most of the drugs commonly used to treat lupus, including cyclophosphamide, which is used only for severe lupus cases.

The researchers concluded that the risk of lymphoma in lupus patients who took cyclophosphamide was less than 0.1 percent per year. In addition, there was no link between lupus disease activity and lymphoma risk, according to the study recently published in the journal Annals of the Rheumatic Diseases.

"People have been wondering for a long time whether the medications were to blame and the results are reassuring, suggesting that most lymphoma cases in SLE are not triggered by drug exposures," first and corresponding author Dr. Sasha Bernatsky, a researcher in the divisions of clinical epidemiology and rheumatology at the Research Institute of the McGill University Health Center, said in a university news release.

Future research will look at how lupus patients' genetics might influence the interaction between medication and lymphoma risk.

More information

The U.S. National Institute of Arthritis and Musculoskeletal Diseases has more about lupus.